1. Field of the Invention
The present invention relates to an image forming apparatus and a fixing device and more particularly to an image forming apparatus, a fixing device, and a fixing device control method in which the temperature control method for the fixing device is improved.
2. Description of the Related Art
Conventionally, as disclosed in Japanese Patent Application Publication No. 2003-330312, there is an image forming apparatus in consideration of shortening the time required for a heat roller to reach the fixing temperature when the switch thereof is turned on. The fixing temperature means the temperature of the heat roller at the time of the toner on a recording sheet being fixed.
A heater lamp of such a fixing device, after the heat roller reaches the fixing temperature, until the overshooting heat roller returns to the set temperature, may be kept in the heater lamp off state for a certain period of time. When taking a copy in the state that the heater lamp is off for some time after warming up, the heat roller loses heat to the pressing roller and a recording sheet simultaneously with rotation of the fixing device, and the temperature of the heat roller falls suddenly, and defective fixing may be caused.